Long reinforcement strategies for underground mines

由于对矿物资源的需求增加，已导致开采较深的矿石储备和使用生产率较高的采矿方法。在这种情况下，在恶劣的地面条件下保持地下开挖的稳定性是主要的工程挑战之一。岩石失稳是地下矿山伤害的最大原因，可能导致采矿作业暂停和关闭。当围岩破坏区域向墙内延伸较深时，传统的锚杆已不够用，需要采用较长的锚杆等加固单元来支撑开挖。电缆螺栓是由多股钢绞线组成的高容量长柔性接地加固筋。它们的性能大多是由实验室测试确定的，很难将其结果推断到现场条件。锚索锚固策略是基于经验方法，参考理想条件，只包括少数可用的锚杆类型，并不是适用于所有的开挖墙。电缆螺栓仪表提供了电缆性能的有用信息，但不能完全集成到支架设计中。数值模拟可以补充仪器数据，为制定锚杆策略提供合理和可靠的方法。这要求我们对锚索的行为有很好的理解，并且要求数值模型能够再现各种类型锚索在不同条件下的显式行为。提出的研究计划旨在通过进场和非进场地下开挖的现场拉拔试验和现场试验，提高我们对不同类型锚杆性能的理解。现场监测，包括先进的3D激光扫描方法、延伸计和仪表螺栓，将允许在不同的现场条件下表征不同电缆螺栓类型和配置的性能。复杂的三维数值模拟方法将用于明确捕获不同锚索的性能和三维破坏区域在不同阶段的进入和非进入开挖。该计划将建立在我以前的工作上，使用仪器和先进的岩石破坏机制和加固行为的明确建模。这将增加我们对锚索在现场力学性能的了解。研究结果将为电缆螺栓设计提供改进的指导方针和工具，并最终提高地下作业的安全性和成本效益。加拿大的采矿业是加拿大经济财富的主要贡献者，但能够从事地面控制工作的高素质人才严重短缺。该方案将有助于培养研究生谁将获得理论知识和现场经验，应用基本原则来解决实际问题的矿山。

The increased need for mineral resources has lead to the exploitation of deeper ore reserves and the use of mining methods with higher production rates. In these conditions, one of the main engineering challenges is to maintain the stability of underground excavations under difficult ground conditions. Rock instability is the biggest cause of injuries in underground mines and can result in the suspension and closure of mining operations. When the zone of failure in the rock extends deep inside the walls, traditional rock bolts are not adequate and the use of longer reinforcement units, such as cable bolts is necessary to support the excavation. Cable bolts are high capacity long flexible ground reinforcement tendons comprised of multi wire strand. Their performance has been mostly determined from laboratory tests and is difficult to extrapolate their results to field conditions. Cable bolting strategies are based on empirical methods that refer to ideal conditions, include only a few of the available bolt types and are not applicable to all the excavation walls. Instrumented cable bolts provide useful information of cable performance but are not fully integrated in the support design. Numerical modelling can complement instrumentation data to provide a rational and robust approach for developing cable bolt strategies. This requires that we have a good understanding of the behaviour of cable bolts and that numerical models can reproduce the explicit behaviour of various cable bolt types under different conditions. The proposed research program aims on improving our understanding on the behaviour of different cable bolt types through in-situ pull tests and field trials in entry and non-entry underground excavations. Field monitoring, including advanced 3D laser scanning methods, extensometers and instrumented bolts will allow to characterize the performance of different cable bolt types and configurations under different conditions in the field. Sophisticated 3D numerical modelling methods will be used to capture explicitly the performance of the different cables and the 3D zone of failure in different stages of entry and non-entry excavations. The program will build on my previous work on the use of instrumentation and advanced explicit modelling of the rock failure mechanism and the behaviour of reinforcement. It will allow to increase our knowledge on the in-situ mechanical behaviour of the cables. The results will provide improved guidelines and tools for cable bolt design and ultimately improve the safety and cost effectiveness of underground operations. The Canadian mining industry is a main contributor to the economic wealth of Canada and has a significant shortage of highly qualified personnel that can work in ground control. The program will contribute significantly to the training of graduate students who will gain theoretical knowledge and field experience applying fundamental principles to solve real problems at mines.